1. Field of the Invention
The present disclosure relates to a liquid drop ejecting head, an image forming device including a liquid drop ejecting head, and a method of manufacturing a liquid drop ejecting head.
2. Description of the Related Art
Generally, an image forming device including a liquid drop ejecting head to eject liquid drops, such as ink, is known as one of various image forming devices, including printers, fax devices, copiers, plotters, multi-function peripherals, etc. In this image forming device, the liquid drop ejecting head ejects ink drops to a print medium which is intermittently transported, so that an image is formed on the print medium by the ink drops adhering thereto.
In the following, the print medium on which the image is formed by the image forming device of the liquid drop ejecting type may include printing sheets (paper), thread, fibers, textile, leather, metal, plastics, glass, wood, and ceramics. The image formation performed by the image forming device of the liquid drop ejecting type may include image formation of meaningful images, such as characters or figures, and image formation of meaningless images, such as patterns, (or liquid drops are ejected to the target object).
The ink used in the image forming device of the liquid drop ejecting type may include a printing liquid, a fixing process solution and any other liquid, which are commonly used to perform image formation, and may further include DNA samples, resist materials, pattern materials, resins, etc.
The image formed by the image forming device of the liquid drop ejecting type may include two-dimensional images, three-dimensionally formed images, and images of three-dimensionally formed solid models.
Conventionally, there is known a piezoelectric liquid drop ejecting head which includes plural liquid chambers individually arranged for plural nozzles arrayed in parallel to eject ink drops. In this piezoelectric liquid drop ejecting head, a diaphragm is formed at a part of a wall surface of each of the liquid chambers. The diaphragm is deformed by a pressure generating means, such as a piezoelectric element, and the volume of the liquid chamber is changed to eject an ink drop from the nozzle.
In recent years, in order to meet the demand for a high level of image quality in image forming devices, reduction of ink drop size has been proposed. In order to eject an ink drop the volume of which ranges from several picoliters (pL) to several tens of picoliters (pL) from a minute nozzle straightly with good stability, it is important to prevent the inclusion of foreign substances in the liquid drop ejecting head.
If a foreign substance mixed in an ink manufacturing process or a foreign substance adhering to an ink supply module is present, the foreign substance is moved to the nozzle by liquid drops so that the nozzle may be clogged with the foreign substance (which causes insufficient ejection) or the foreign substance may partially adhere to the nozzle end (which causes ejection deviation).
In order to prevent occurrence of insufficient ejection due to foreign substances, a method of arranging a filter for capturing foreign substances in a liquid drop ejecting head is known. For example, see Japanese Laid-Open Patent Publication No. 2008-213196.
This filter is arranged in the vicinity of a nozzle as close as possible, the area in which cleanliness can be secured is narrowed by the filter, and it is possible to maintain the cleanliness stably at a high level. Japanese Laid-Open Patent Publication No. 2008-213196 discloses a liquid drop ejecting head in which a filter part is formed in a diaphragm component that forms one wall surface of a pressurizing liquid chamber as an ink passage.
FIG. 16 shows a liquid drop ejecting head disclosed in Japanese Laid-Open Patent Publication No. 2008-213196. As shown in the area indicated by a dotted line in FIG. 16, a portion of a channel member 1 adjacent to a filter part 9 is arranged to overlap with a 3-layered structure portion of a diaphragm 2, and the channel member 1 portion is mounted on the diaphragm 2 portion in the laminating direction thereof.
In a method of manufacturing the above liquid drop ejecting head, in order to secure a bonding strength of the channel plate and the diaphragm, pressure bonding is performed on the diaphragm 3-layered structure portion and the channel plate portion overlapping in the laminating direction by using an upper pressurizing jig on the top of the channel plate and a lower pressurizing jig on the bottom of the diaphragm, respectively.
However, in a case of the pressure bonding method, an adhesive applied between the channel member and the diaphragm may flow out due to the pressurization. If the adhesive reaches the filter part formed in the diaphragm, the adhesive passes through the filtering holes by the capillary effect and such adhesive flows out. The adhesive may stick to the pressurizing jigs, and the yield may fall.